Cable local defect positioning method and device, electronic equipment and storage medium

Abstract

The invention discloses a cable local defect positioning method and device, electronic equipment and a storage medium, and is used for solving the technical problem that a positioning map is distorted due to noise interference existing in an existing cable defect positioning method. The method comprises the following steps: measuring a head end impedance spectrum of a defective cable; converting the head-end impedance spectrum into a head-end reflection coefficient spectrum; obtaining a Kasami sequence incident signal; calculating a time domain reflection signal of the Kasami sequence incident signal by adopting the head end reflection coefficient spectrum; performing cross-correlation on the time domain reflection signal and the Kasami sequence incident signal to obtain a cross-correlation result; performing time-space domain conversion on the cross-correlation result to generate a positioning map of the defective cable; and carrying out local defect positioning on the defective cable by adopting the positioning map.

Description

Technical Field

[0001] The present invention relates to the technical field of cable defect positioning, and in particular to a cable local defect positioning method, device, electronic equipment and storage medium. Background Art

[0002] With the continuous advancement of urbanization, power distribution networks based on power cables are widely used. However, cables are easily damaged during production, transportation and use, resulting in local defects in the cables, which can easily lead to insulation breakdown accidents during cable operation, causing direct or indirect economic losses. Most cable defects are local or latent defects, and traditional cable defect detection methods are insensitive to such defects, leaving safety risks for cable operation.

[0003] At present, the commonly used cable local defect detection methods are as follows:

[0004] 1. Time domain reflectometry (TDR): In TDR testing, the terminal load is generally set to an open circuit, and a pulse power supply is used as the test power supply. A low-voltage, high-frequency pulse signal is input from the input end to the cable. The received reflected signal is recorded from the input end, including the reflection at the defect and the terminal reflection. By comparing the time difference between the incident signal and the reflected signal, combined with the cable length and the signal transmission speed in the cable, the cable defect location can be obtained.

[0005] 2. Time-frequency domain reflectometry (TFDR): Different from TDR, TFDR uses a signal generator as the test power source to input a Gaussian envelope narrowband signal to the cable under test. TFDR has the advantages of TDR and can adjust the frequency range of the input signal, making it easier to control the waveform of the input signal before testing.

[0006] 3. Broadband impedance spectrum (BIS) based on frequency domain reflectometry (FDR): BIS uses a swept frequency power supply to input a linear swept frequency signal to the cable under test and receives the reflected signal at the input end. Since the characteristic parameters of the cable are determined by the cable itself, the broadband impedance spectrum of the cable under test can be obtained by analyzing the relationship between the incident signal and the reflected signal, and then the obtained broadband impedance spectrum is converted from frequency domain to time domain to obtain the positioning map of the cable under test.

[0007] However, when using the TDR method for measurement, different input waveforms need to be selected for cables of different sizes and lengths. In addition, the TDR method has few high-frequency components and limited sensitivity to defect detection. TFDR uses a signal generator as the input power supply to input a high-envelope narrowband signal to the cable under test. The frequency range is controllable, which solves the problem of few high-frequency components of TDR. However, the defect detection sensitivity of the TFDR method is limited. When the signal is severely attenuated and dispersed during transmission, the positioning effect will be weakened.

[0008] Compared with TDR and TFDR methods, the power of FDR input signal is constant within the set frequency band, the signal will not have obvious dispersion and attenuation, and the positioning accuracy is higher. However, since white noise in the frequency domain may be introduced during the test of BIS data, the noise signal will also be converted into the positioning map through inverse Fourier transform, causing the positioning map to be distorted. Summary of the invention

[0009] The present invention provides a cable local defect positioning method, device, electronic device and storage medium, which are used to solve the technical problem that the existing cable defect positioning method has noise interference, resulting in distortion of the positioning map.

[0010] The present invention provides a method for locating local defects in a cable, comprising:

[0011] Measure the impedance spectrum of the defective cable at the first end;

[0012] Converting the first-end impedance spectrum into a first-end reflection coefficient spectrum;

[0013] Obtain the Kasami sequence incident signal;

[0014] Calculating the time domain reflection signal of the Kasami sequence incident signal using the head-end reflection coefficient spectrum;

[0015] Cross-correlating the time domain reflection signal with the Kasami sequence incident signal to obtain a cross-correlation result;

[0016] Performing time-space domain conversion on the cross-correlation result to generate a location map of the defective cable;

[0017] The positioning map is used to locate local defects of the defective cable.

[0018] Optionally, the step of converting the first-end impedance spectrum into a first-end reflection coefficient spectrum includes:

[0019] Obtaining the characteristic impedance of the defective cable;

[0020] The characteristic impedance and the first-end impedance spectrum are used to generate a first-end reflection coefficient spectrum.

[0021] Optionally, the step of acquiring a Kasami sequence incident signal includes:

[0022] Obtaining an initial sequence of a preset order and a preset length;

[0023] Circularly shifting the initial sequence rightward by a preset offset to obtain a new sequence;

[0024] A modulo-2 addition operation is performed on the initial sequence and the new sequence to obtain a Kasami sequence as a Kamami sequence incident signal.

[0025] Optionally, the step of calculating the time domain reflection signal of the Kasami sequence incident signal by using the head-end reflection coefficient spectrum includes:

[0026] Acquire the time domain waveform of the Kasami sequence incident signal;

[0027] Converting the time domain waveform into a frequency domain waveform;

[0028] The time domain reflection signal of the Kasami sequence incident signal is generated by using the head-end reflection coefficient spectrum and the frequency domain waveform.

[0029] Optionally, the step of cross-correlating the time domain reflection signal and the Kasami sequence incident signal to obtain a cross-correlation result includes:

[0030] Obtaining the duration of the time domain reflection signal;

[0031] Calculating a time delay between the time domain signal and the time domain reflection signal;

[0032] The time domain reflection signal, the duration and the delay are used to calculate a cross-correlation result between the time domain reflection signal and the Kasami sequence incident signal.

[0033] Optionally, the step of performing time-space domain conversion on the cross-correlation result to generate the location map of the defective cable includes:

[0034] Get the signal transmission distance on the defective cable;

[0035] The signal transmission distance is used as the horizontal coordinate and the cross-correlation result is used as the vertical coordinate to generate a positioning map of the defective cable.

[0036] The present invention also provides a cable local defect locating device, comprising:

[0037] The first-end impedance spectrum measurement module is used to measure the first-end impedance spectrum of the defective cable;

[0038] A first-end reflection coefficient spectrum conversion module, used to convert the first-end impedance spectrum into a first-end reflection coefficient spectrum;

[0039] A Kasami sequence incident signal acquisition module, used to acquire a Kasami sequence incident signal;

[0040] A time domain reflection signal calculation module, used to calculate the time domain reflection signal of the Kasami sequence incident signal using the head-end reflection coefficient spectrum;

[0041] A cross-correlation module, used for cross-correlating the time domain reflection signal and the Kasami sequence incident signal to obtain a cross-correlation result;

[0042] A positioning map generation module, used for performing time-space domain conversion on the cross-correlation result to generate a positioning map of the defective cable;

[0043] A local defect locating module is used to use the locating map to locate the local defects of the defective cable.

[0044] Optionally, the head-end reflection coefficient spectrum conversion module includes:

[0045] A characteristic impedance acquisition submodule, used to acquire the characteristic impedance of the defective cable;

[0046] The head-end reflection coefficient spectrum generating submodule is used to generate a head-end reflection coefficient spectrum by using the characteristic impedance and the head-end impedance spectrum.

[0047] The present invention also provides an electronic device, the device comprising a processor and a memory:

[0048] The memory is used to store program code and transmit the program code to the processor;

[0049] The processor is used to execute the cable local defect locating method as described in any one of the above items according to the instructions in the program code.

[0050] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store program codes, and the program codes are used to execute the cable local defect locating method as described in any one of the above items.

[0051] It can be seen from the above technical scheme that the present invention has the following advantages: the present invention measures the impedance spectrum of the head end of the defective cable; converts the impedance spectrum of the head end into the reflection coefficient spectrum of the head end; obtains the Kasami sequence incident signal; uses the reflection coefficient spectrum of the head end to calculate the time domain reflection signal of the Kasami sequence incident signal; cross-correlates the time domain reflection signal and the Kasami sequence incident signal to obtain the cross-correlation result; converts the cross-correlation result into the time-space domain to generate the positioning spectrum of the defective cable; and uses the positioning spectrum to perform local defect positioning on the defective cable. Thus, the noise interference in the cable defect positioning process is eliminated, and the accuracy of local defect positioning is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0053] Figure 1 A flowchart of the steps of a cable local defect locating method provided by an embodiment of the present invention;

[0054] Figure 2 A flowchart of a method for locating local defects in a cable provided by another embodiment of the present invention;

[0055] Figure 3 Schematic diagram of the simulation method of the Kasami sequence incident signal;

[0056] Figure 4a Schematic diagram of the time domain spectrum of Kasami sequences of different orders;

[0057] Figure 4b Schematic diagram of frequency domain spectra of Kasami sequences of different orders;

[0058] Figure 5a Schematic diagram of the output waveform of the BIS result analysis for the cable local defect location method;

[0059] Figure 5b This is a schematic diagram of the output waveform of the BIS result analysis using the IFFT method;

[0060] Figure 6 A structural block diagram of a cable local defect locating device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0061] The embodiments of the present invention provide a cable local defect positioning method, device, electronic device and storage medium, which are used to solve the technical problem that the existing cable defect positioning method has noise interference, resulting in distortion of the positioning map.

[0062] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] See also Figure 1 , Figure 1 A flowchart of the steps of a cable local defect locating method provided by an embodiment of the present invention.

[0064] The present invention provides a method for locating local defects in a cable, which may specifically include the following steps:

[0065] Step 101, measuring the impedance spectrum of the first end of the defective cable;

[0066] In the embodiment of the present invention, a vector network analyzer (VNA) may be used to measure the first-end impedance spectrum BIS of the defective cable.

[0067] Step 102, converting the first-end impedance spectrum into a first-end reflection coefficient spectrum;

[0068] The first-end reflection coefficient refers to the ratio of the reflected voltage to the incident voltage. The reflection coefficient is an important parameter to measure the reflection size, indicating the relationship between the intensity of the reflected signal and the intensity of the incident signal. The first-end reflection coefficient spectrum reflects the change of the first-end reflection coefficient over time.

[0069] Step 103, obtaining a Kasami sequence incident signal;

[0070] The Kasami sequence is a type of pseudo-random sequence with excellent autocorrelation, and the correlation between different Kasami sequences is small. The embodiment of the present invention uses the Kasami sequence as a simulated incident signal to improve the anti-noise capability of the positioning map.

[0071] Step 104, using the head-end reflection coefficient spectrum to calculate the time domain reflection signal of the Kasami sequence incident signal;

[0072] The time domain describes the relationship between a mathematical function or a physical signal and time. For example, the time domain waveform of a signal can express how the signal changes over time.

[0073] After the Kasami sequence incident signal is obtained, the time domain reflection signal of the Kasami sequence incident signal can be calculated in combination with the head-end reflection coefficient spectrum.

[0074] Step 105, cross-correlating the time domain reflection signal and the Kasami sequence incident signal to obtain a cross-correlation result;

[0075] Step 106, converting the cross-correlation result into a time-space domain to generate a location map of the defective cable;

[0076] After the time domain reflection signal is obtained, the Kasami sequence incident signal and its time domain reflection signal are cross-correlated, and then a positioning map of the defective cable is generated based on the cross-correlation result.

[0077] Step 107, using the positioning map to locate the local defect of the defective cable.

[0078] After obtaining the positioning map, the local defect position of the defective cable can be obtained from the positioning map, thereby realizing the local defect positioning of the defective cable.

[0079] The present invention measures the impedance spectrum of the head end of the defective cable; converts the impedance spectrum of the head end into the reflection coefficient spectrum of the head end; obtains the Kasami sequence incident signal; uses the reflection coefficient spectrum of the head end to calculate the time domain reflection signal of the Kasami sequence incident signal; cross-correlates the time domain reflection signal and the Kasami sequence incident signal to obtain the cross-correlation result; converts the cross-correlation result into the time-space domain to generate the positioning spectrum of the defective cable; and uses the positioning spectrum to perform local defect positioning on the defective cable. Thus, the noise interference in the cable defect positioning process is eliminated, and the accuracy of local defect positioning is improved.

[0080] See also Figure 2 , Figure 2 A flowchart of a method for locating local defects in a cable provided in another embodiment of the present invention. Specifically, the following steps may be included:

[0081] Step 201, measuring the impedance spectrum of the first end of the defective cable;

[0082] Step 201 is the same as step 101. For details, please refer to the description of step 101, which will not be repeated here.

[0083] Step 202, obtaining the characteristic impedance of the defective cable;

[0084] Step 203, generating a head-end reflection coefficient spectrum using characteristic impedance and head-end impedance spectrum;

[0085] Characteristic impedance, also called characteristic impedance, is the inherent property of RF transmission lines that affects the amplitude and phase changes of radio wave voltage and current, and is equal to the ratio of voltage to current at each location.

[0086] In the embodiment of the present invention, the specific formula for converting the first-end impedance spectrum into the first-end reflection coefficient spectrum is as follows:

[0087]

[0088] in, is the reflection coefficient spectrum of the first end; is the measured impedance spectrum of the first end; is the characteristic impedance of the cable line.

[0089] Step 204, obtaining a Kasami sequence incident signal;

[0090] The Kasami sequence is a type of pseudo-random sequence with excellent autocorrelation, and the correlation between different Kasami sequences is small. The embodiment of the present invention uses the Kasami sequence as a simulated incident signal to improve the anti-noise capability of the positioning map.

[0091] In one example, the step of obtaining a Kasami sequence incident signal includes:

[0092] S41, obtaining an initial sequence of a preset order and a preset length;

[0093] S42, cyclically shifting the initial sequence rightward by a preset offset to obtain a new sequence;

[0094] S43, performing a modulo-2 addition operation on the initial sequence and the new sequence to obtain a Kasami sequence as a Kamami sequence incident signal.

[0095] In a specific implementation, the simulation method of the Kasami sequence incident signal can be as follows: Figure 3 As shown. First, the computer generates a sequence of order n and length The initial sequence m_seq1, where n is a positive integer.

[0096] by is the offset (if n / 2 is not an integer, round it down), and m_seq1 is circularly shifted right The new sequence m_seq2 is obtained.

[0097] A modulo-2 addition operation (ie, exclusive OR operation, XOR) is performed on the sequence m_seq1 and the sequence m_seq2 to obtain a Kasami sequence Kasami_seq with a code length of N.

[0098] The time domain and frequency domain spectra of Kasami sequences of different orders generated according to the above steps are shown in FIG4 .

[0099] Step 205, using the head-end reflection coefficient spectrum to calculate the time domain reflection signal of the Kasami sequence incident signal;

[0100] After the Kasami sequence incident signal is obtained, the time domain reflection signal of the Kasami sequence incident signal can be calculated in combination with the head-end reflection coefficient spectrum.

[0101] In one example, the step of calculating the time domain reflection signal of the Kasami sequence incident signal using the head-end reflection coefficient spectrum includes:

[0102] S51, obtaining a time domain waveform of a Kasami sequence incident signal;

[0103] S52, converting the time domain waveform into a frequency domain waveform;

[0104] S53, using the head-end reflection coefficient spectrum and the frequency domain waveform to generate a time domain reflection signal of the Kasami sequence incident signal.

[0105] In a specific implementation, the head-end reflection coefficient can be obtained by using inverse Fourier transform to obtain the time domain reflection signal of the Kasami sequence incident signal, and its formula is as follows:

[0106]

[0107] in, , Respectively represent the time domain waveform and frequency domain waveform of the Kasami sequence incident signal, A time domain waveform representing a time domain reflection signal.

[0108] Step 206, cross-correlating the time domain reflection signal and the Kasami sequence incident signal to obtain a cross-correlation result;

[0109] In this embodiment of the present invention, step 206 may include the following sub-steps:

[0110] S61, obtaining the duration of the time domain reflection signal;

[0111] S62, calculating the time delay between the time domain signal and the time domain reflection signal;

[0112] S63, using the time domain reflection signal, the duration and the delay to calculate the cross-correlation result between the time domain reflection signal and the Kasami sequence incident signal.

[0113] In a specific implementation, the formula for performing a cross-correlation operation on the time domain reflection signal and the Kasami sequence incident signal is as follows:

[0114]

[0115] in, Real signal and noise Two parts, for and Ts is the time delay between reflection signals; Ts is the time delay between reflection signals; Ts is the time delay between reflection signals; Ts is the time delay between reflection signals and noise The cross-correlation result is approximately zero, so the noise signal will be eliminated in the result of cross-correlation operation between the time domain reflection signal and the Kasami sequence incident signal, and the cross-correlation result is approximately the real signal, so the result can be simplified as:

[0116]

[0117] Calculated by the above formula It not only retains the amplitude and delay characteristics of the real signal, but also filters out the interference of the noise signal.

[0118] Step 207, converting the cross-correlation result into time-space domain to generate a location map of the defective cable;

[0119] In one example, step 207 may include the following sub-steps:

[0120] S71, obtaining a signal transmission distance on the defective cable;

[0121] S72, using the signal transmission distance as the horizontal coordinate and the cross-correlation result as the vertical coordinate to generate a positioning map of the defective cable.

[0122] In the specific implementation, the conversion process of converting the cross-correlation result into the time-space domain to obtain the positioning map is as follows:

[0123]

[0124] in, is the transmission speed of electromagnetic waves in a vacuum, i.e. 3×10 8 m / s; is the propagation speed of electromagnetic waves in the cable, approximately equal to 1.75×10 8 m / s. is the distance the signal is transmitted on the cable under test, and is the horizontal coordinate of the positioning spectrum; is the vertical coordinate of the positioning map; is the magnetic permeability in vacuum; is the dielectric constant of vacuum; is the relative dielectric constant, which is generally 2.3 for the cross-linked polyethylene insulation of the cable.

[0125] Step 208: Use the positioning map to locate the local defect of the defective cable.

[0126] After obtaining the positioning map, the local defect position of the defective cable can be obtained from the positioning map, thereby realizing the local defect positioning of the defective cable.

[0127] In one example, a BIS test is performed on a coaxial cable of 750 m in length with three intermediate joints, and the BIS results are analyzed using the cable local defect location method and the IFFT method according to the embodiment of the present invention, respectively. The results are shown in FIG5 , where: Figure 5a is the positioning waveform of the IFFT method, Figure 5b It is the positioning waveform of the cable local defect positioning method. As shown in Figure 5, compared with the IFFT method, the positioning spectrum obtained by the cable local defect positioning method of the embodiment of the present invention clearly reflects the positions of the cable ends and the middle joints, and the noise interference in the spectrum is significantly reduced. Changing the order can further improve the spectrum effect, indicating that the cable local defect positioning method of the embodiment of the present invention has good noise resistance and significantly improves the spatial resolution of the positioning spectrum.

[0128] The present invention measures the impedance spectrum of the head end of the defective cable; converts the impedance spectrum of the head end into the reflection coefficient spectrum of the head end; obtains the Kasami sequence incident signal; uses the reflection coefficient spectrum of the head end to calculate the time domain reflection signal of the Kasami sequence incident signal; cross-correlates the time domain reflection signal and the Kasami sequence incident signal to obtain the cross-correlation result; converts the cross-correlation result into the time-space domain to generate the positioning spectrum of the defective cable; and uses the positioning spectrum to perform local defect positioning on the defective cable. Thus, the noise interference in the cable defect positioning process is eliminated, and the accuracy of local defect positioning is improved.

[0129] See also Figure 6 , Figure 6 A structural block diagram of a cable local defect locating device provided in an embodiment of the present invention.

[0130] An embodiment of the present invention provides a cable local defect locating device, comprising:

[0131] The first-end impedance spectrum measurement module 601 is used to measure the first-end impedance spectrum of the defective cable;

[0132] A first-end reflection coefficient spectrum conversion module 602, used to convert the first-end impedance spectrum into a first-end reflection coefficient spectrum;

[0133] A Kasami sequence incident signal acquisition module 603, used to acquire a Kasami sequence incident signal;

[0134] A time domain reflection signal calculation module 604 is used to calculate the time domain reflection signal of the Kasami sequence incident signal using the head end reflection coefficient spectrum;

[0135] A cross-correlation module 605 is used to cross-correlate the time domain reflection signal and the Kasami sequence incident signal to obtain a cross-correlation result;

[0136] A positioning map generation module 606 is used to convert the cross-correlation results into time-space domain to generate a positioning map of the defective cable;

[0137] The local defect positioning module 607 is used to use the positioning map to perform local defect positioning on the defective cable.

[0138] In the embodiment of the present invention, the head-end reflection coefficient spectrum conversion module 602 includes:

[0139] A characteristic impedance acquisition submodule is used to obtain the characteristic impedance of the defective cable;

[0140] The first-end reflection coefficient spectrum generating submodule is used to generate the first-end reflection coefficient spectrum by using the characteristic impedance and the first-end impedance spectrum.

[0141] In the embodiment of the present invention, the Kasami sequence incident signal acquisition module 603 includes:

[0142] An initial sequence acquisition submodule is used to acquire an initial sequence of a preset order and a preset length;

[0143] The cyclic right shift submodule is used to cyclically shift the initial sequence right by a preset offset to obtain a new sequence;

[0144] The modulo-2 addition operation submodule is used for performing a modulo-2 addition operation on the initial sequence and the new sequence to obtain a Kasami sequence as a Kamami sequence incident signal.

[0145] In the embodiment of the present invention, the time domain reflection signal calculation module 604 includes:

[0146] A time domain waveform acquisition submodule is used to acquire the time domain waveform of the Kasami sequence incident signal;

[0147] Convert the time domain waveform into a frequency domain waveform;

[0148] The time domain reflection signal generation submodule is used to generate the time domain reflection signal of the Kasami sequence incident signal by using the head-end reflection coefficient spectrum and the frequency domain waveform.

[0149] In this embodiment of the present invention, the cross-correlation module 605 includes:

[0150] Duration acquisition submodule, the user obtains the duration of the time domain reflection signal;

[0151] The delay calculation submodule is used to calculate the delay between the time domain signal and the time domain reflection signal;

[0152] The cross-correlation submodule is used to calculate the cross-correlation result of the time domain reflection signal and the Kasami sequence incident signal by using the time domain reflection signal, the duration and the delay.

[0153] In the embodiment of the present invention, the positioning map generation module 606 includes:

[0154] A signal transmission distance acquisition submodule is used to acquire the signal transmission distance on the defective cable;

[0155] The positioning map generation submodule is used to generate a positioning map of the defective cable using the signal transmission distance as the horizontal coordinate and the cross-correlation result as the vertical coordinate.

[0156] An embodiment of the present invention further provides an electronic device, the device comprising a processor and a memory:

[0157] The memory is used to store the program code and transmit the program code to the processor;

[0158] The processor is used to execute the cable local defect locating method according to the instructions in the program code.

[0159] The embodiment of the present invention further provides a computer-readable storage medium, which is used to store program codes, and the program codes are used to execute the cable local defect locating method of the embodiment of the present invention.

[0160] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0161] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0162] It will be appreciated by those skilled in the art that the embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0163] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0164] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0165] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable terminal device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0166] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0167] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0168] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cable local defect location method, characterized in that: include: Measure the impedance spectrum of the defective cable at the first end; Converting the first-end impedance spectrum into a first-end reflection coefficient spectrum; Obtain the Kasami sequence incident signal; Calculating the time domain reflection signal of the Kasami sequence incident signal using the head-end reflection coefficient spectrum; Cross-correlating the time domain reflection signal with the Kasami sequence incident signal to obtain a cross-correlation result; Performing time-space domain conversion on the cross-correlation result to generate a location map of the defective cable; The positioning map is used to locate local defects of the defective cable.

2. The method according to claim 1, characterized in that The step of converting the first-end impedance spectrum into a first-end reflection coefficient spectrum comprises: Obtaining the characteristic impedance of the defective cable; The characteristic impedance and the first-end impedance spectrum are used to generate a first-end reflection coefficient spectrum.

3. The method according to claim 1, characterized in that The step of obtaining the Kasami sequence incident signal comprises: Obtaining an initial sequence of a preset order and a preset length; Circularly shifting the initial sequence rightward by a preset offset to obtain a new sequence; A modulo-2 addition operation is performed on the initial sequence and the new sequence to obtain a Kasami sequence as a Kamami sequence incident signal.

4. The method according to claim 1, characterized in that: The step of using the head-end reflection coefficient spectrum to calculate the time domain reflection signal of the Kasami sequence incident signal comprises: Acquire the time domain waveform of the Kasami sequence incident signal; Converting the time domain waveform into a frequency domain waveform; The time domain reflection signal of the Kasami sequence incident signal is generated by using the head-end reflection coefficient spectrum and the frequency domain waveform.

5. The method according to claim 1, characterized in that: The step of cross-correlating the time domain reflection signal and the Kasami sequence incident signal to obtain a cross-correlation result includes: Obtaining the duration of the time domain reflection signal; Calculating a time delay between the time domain signal and the time domain reflection signal; The time domain reflection signal, the duration and the delay are used to calculate a cross-correlation result between the time domain reflection signal and the Kasami sequence incident signal.

6. The method according to claim 1, characterized in that The step of converting the cross-correlation result into a time-space domain to generate a location map of the defective cable comprises: Get the signal transmission distance on the defective cable; The signal transmission distance is used as the horizontal coordinate and the cross-correlation result is used as the vertical coordinate to generate a positioning map of the defective cable.

7. A cable local defect locating device, characterized in that: include: The first-end impedance spectrum measurement module is used to measure the first-end impedance spectrum of the defective cable; A first-end reflection coefficient spectrum conversion module, used to convert the first-end impedance spectrum into a first-end reflection coefficient spectrum; A Kasami sequence incident signal acquisition module, used to acquire a Kasami sequence incident signal; A time domain reflection signal calculation module, used to calculate the time domain reflection signal of the Kasami sequence incident signal using the head-end reflection coefficient spectrum; A cross-correlation module, used for cross-correlating the time domain reflection signal and the Kasami sequence incident signal to obtain a cross-correlation result; A positioning map generation module, used for performing time-space domain conversion on the cross-correlation result to generate a positioning map of the defective cable; A local defect locating module is used to use the locating map to locate the local defects of the defective cable.

8. The device according to claim 7, characterized in that The head-end reflection coefficient spectrum conversion module comprises: A characteristic impedance acquisition submodule, used to acquire the characteristic impedance of the defective cable; The head-end reflection coefficient spectrum generating submodule is used to generate a head-end reflection coefficient spectrum by using the characteristic impedance and the head-end impedance spectrum.

9. An electronic device, characterized in that: The device comprises a processor and a memory: The memory is used to store program codes and transmit the program codes to the processor; The processor is used to execute the cable local defect locating method according to any one of claims 1-6 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store program codes, and the program codes are used to execute the cable local defect locating method according to any one of claims 1-6.

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